Summary A Fokker F-28 MK 1000 aircraft, C-GKCR, serial number11101, operated as flight8604 by Canadian Regional Airlines, was on a scheduled, night passenger flight from Toronto, Ontario, to Fredericton, NewBrunswick. On board were 42passengers and four crew members. After landing on runway09 in Fredericton, the aircraft overran the end of the runway. There were no injuries to passengers or crew, and there was no damage to the aircraft. Ce rapport est galement disponible en franais. Other Factual Information The en route flight was uneventful. At 0122 Atlantic standard time,1 the crew advised the Fredericton Flight Service Station (FSS) that they were 18minutes from the airport and requested current Fredericton weather for their approach. The FSS specialist reported that visibility was as low as 4statute miles in snow, winds were from 020 magnetic at 7knots, and the temperature was 0.4C. The FSS specialist also advised that sweepers were sweeping a thin layer of slush from the centreline of runway15/33 but that the official runway surface condition (RSC) report was 100%bare and wet. The crew indicated that, since wind were favouring runway09, they would like runway09 to be swept. At 0125, 19minutes before the aircraft touched down, vehicles were cleared to sweep Runway09. At 0134, Moncton Area Control Centre advised the FSS specialist that the flight was cleared for a straight-in approach to runway09, with the option to circle for landing on Runway33. At 0135, the FSS specialist passed an RSC report for runway09 to the flight crew. The RSC was reported to be, on a 100-footcentreline, 50%bare and wet and 50%thin slush with inch of slush on the sides. The crew responded that they received the information, were estimating arrival in five minutes, and had been cleared for a VOR (VHF omnidirectional radio range) approach to runway 09, with the option to circle to the south for landing on runway33. Since they had the option to land on either runway, the crew requested that snow removal vehicles be cleared from all runways. At 0137, the FSS specialist passed an updated RSC report for runway15/33 indicating that the runway was 100%covered in wet snow and, on a 100-footcentreline, 1inches of slush. The crew were not told that slush was accumulating rapidly on both runways. At 0138, six minutes before touchdown, the final report to the crew of visibility at the airport was 2to 3statute miles, and just before touchdown, the winds were relayed as 010 at 7knots. The aircraft flew an uneventful, straight-in, VOR approach. Flap42 was used for approach and landing, with a landing reference speed (VREF) of 117knots indicated airspeed. Speed brakes were selected out at approximately 100feet above ground level, in accordance with standard operating procedures (SOP). At 0144, the aircraft touched down at 118knots indicated airspeed, approximately 1400feet beyond the threshold of runway09, within the touchdown zone. Lift dumpers had been set to auto-deploy on landing. Immediately after the main wheels touched, the captain backed up auto deployment of the lift dumpers by activating the lift dumpers manually. Brakes were applied approximately one second after nosewheel touchdown. The crew sensed that, although braking action was poor, the anti-skid system was cycling. As the anti-skid system was functioning and provides maximum braking performance, the alternate braking system was not used. The aircraft overran the runway end at 58knots and came to rest about 320feet beyond the end of the runway near the airfield perimeter fence. The flight crew reported the overrun to the FSS, shut down engine No.1, started the auxiliary power unit and selected it, then shut down engine No.2. .Two airfield firefighting vehicles responded to the overrun; the first was cleared onto the airfield at0145. The first airfield firefighting vehicle arrived on site approximately 1minutes after the initial alarm was sounded, and the second arrived about one minute later. The passengers were deplaned in groups and shuttled to the terminal by taxis. Fifteen minutes after the occurrence, an RSC report on runway09 showed that most of the runway was covered in inch of slush. Only the departure end of the runway was still 50%wet and 50%covered in inch of slush. The cockpit voice recorder (CVR) and the flight data recorder (FDR) were shipped to the TSB Engineering Laboratory. Playback of the CVR revealed that it continued to operate for more than 30minutes after the occurrence, overwriting the occurrence information. The FDR yielded useful data, which showed that the flight was routine and that the aircraft touched down on the runway within normal parameters. The data were also used to calculate actual stopping performance achieved during the ground roll. Stopping performance was found to be significantly below that obtainable on a standard wet runway. During the initial part of the landing roll, the deceleration was similar to a deceleration profile for the aircraft without any wheel brake application. No mechanical discrepancies were found that would have contributed to the overrun. Aircraft loading was within its prescribed weight and balance limitations throughout the flight. Calculated weight of the aircraft at landing was 55435pounds. The tires were in good condition and were properly inflated. None of the tires exhibited damage in the form of scuffing or reverted rubber. Intermittent tire skidmarks were found slightly left of the runway centreline, beginning approximately 150feet before the end of the runway and continuing to the runway end. Wheel brake systems functioned normally during static and dynamic tests conducted after the accident. The Canadian Runway Friction Index (CRFI)2 Recommended Landing Distances table was available to the crew; however, readings are not taken for slush-covered runways since CRFI measurements are accurate only for packed snow or ice. Fredericton Airport is a certified, uncontrolled airport at which FSS specialists operate out of the former control tower. The airport has two runways:15/33 is 6000feet long, and 09/27is 5100feet long. The asphalt surfaced runways are 200feet wide and do not have a notable longitudinal slope. Runway15 has an instrument landing system precision approach and is the priority runway for snow-clearing operations. Runways09 and27 are served by non-precision instrument approaches. Runway33 has no instrument approach. It is possible to circle to land on runway33 from other runway approaches; however, the weather at the time of the occurrence did not allow for circling. Charts in the Canadian Regional SOP manual allow crews to calculate landing distances for various weights and CRFI combinations. When a CRFI reading is not available, crews refer to the Runway Surface Condition and CRFI Equivalent chart found in the company SOP or in A.I.P. Canada(Figure1). Using this chart, crews can choose a CRFI equivalent from among typical runway surface contaminants such as water, snow, or ice. This chart does not, however, have a CRFI equivalent for slush contamination. Figure1. RSC and CFRI equivalent. Although the crew did not have the means to establish a calculated friction index, they estimated that the runway friction was equivalent to the lowest value for a wet runway, .3CRFI. Using the .3value and a 2-knot headwind component, the crew calculated a landing distance of 4525feet for Runway09. Using the same methods for Runway15 and applying a 6-knot tailwind component yields a landing distance of 5100feet. The Landing on Slush or Snow chart in the SOP manual, which is used to plan flights, provides data on the maximum landing weight for airports reporting slush or snow contamination of up to 0.5inch. According to this chart, for a 5000-footrunway using flaps42, the maximum landing weight for the aircraft is 52600pounds. The aircraft was about 2835pounds over this weight on landing. Since conditions at the time of departure did not forecast snow, there was no reason to refer to this chart before departure.